Knightmare Batman is a tricky opponent, combining power drain on his jump attacks and most notably, a powerful and permanent basic attack reflect that makes it difficult to inflict damage on him. His ambush can also take down your heroes before you could react, especially when he has high damage.
His "Ambush" causes your first hero to not be able to act (including block or tag) for several seconds, allowing his team to hit you with impunity. It is very similar to a stun, but it is not affected by stun immunity (e.g. Justice League Cyborg).
He does not need to be tagged in to have this effect - the enemy is ambushed at the beginning of the match regardless of his position. This makes him extremely dangerous, especially when he is teamed with massive basic damage dealers (e.g. Justice League Cyborg or Justice League The Flash), instantly KO'ing your first hero with little to no chance of recovery (although the Ambush does not pass onto the second opponent even if the first is KO'ed within the duration).
The reflected damage is calculated before Knightmare Batman's armor reduces his damage taken, meaning the reflected damage can be much higher than what damage he would have taken, and using just one combo on him can result in hitting yourself for heavy damage.
His jump attack power is a small downward projectile that drains 1 bars, but the drain is completely negated if blocked. It is not part of his passive so copies (e.g. Sub-Zero's ice clones) can use it.
- The Joker: When KO'ed, he gives his team 1 bar of power and stun the opponent. This does not require Joker to have high threat, making it a cheap tactic to survive Knightmare Ambush. The stun will give Justice League Cyborg power, however.
- Multiverse Armored Supergirl: Her s3 allows Multiverse teammates to be immune to reflect damage.
- He is based on Batman's appearance in the "Knightmare" sequence in Batman v Superman: Dawn of Justice.